Turning the Awareness Back to the Source is the Dharma Gate of Perfect Penetration of Manas (Manas Training Chapter)

Volume Five of the Śūraṅgama Sūtra Original Text:

Aniruddha immediately rose from his seat, bowed at the Buddha’s feet, and addressed the Buddha: "When I first left home, I was often fond of sleep. The Tathāgata rebuked me, calling me a beast. Hearing the Buddha’s rebuke, I wept and reproached myself. For seven days I did not sleep, and I lost both my eyes. The World-Honored One then revealed to me the ‘Delight in Seeing Illumination Vajra Samādhi.’ Without relying on the eyes, I beheld the ten directions—clearly, profoundly, and truly—as clearly as looking at a fruit in my palm. The Tathāgata confirmed my attainment of Arhatship. Now, the Buddha inquires about perfect penetration. According to what I have realized, revolving the seeing to trace back to the source is supreme."

Explanation:

Aniruddha began his practice from the eye faculty. His insight was "revolving the seeing to trace back to the source." "Revolving" means turning inward—reversing the eye faculty’s habitual outward-directed seeing inward, tracing it back to its origin, the fundamental root. Originally, seeing was directed outward toward external form-objects (rūpa-dharma). Now, it must be reversed to perceive the very source of seeing itself. What is this fundamental source? It is the root that gives rise to the function of seeing. What guides and determines the eye faculty’s seeing? First, it is the mental faculty (manas), and ultimately, it is the eighth consciousness (ālaya-vijñāna). The most fundamental point is the eighth consciousness.

Stabilizing at the mental faculty leads to the attainment of a great Arhat. Stabilizing at the eighth consciousness leads to the attainment of a great Bodhisattva. From the perspective of the conventional world, the mental faculty has the function of perceiving all dharmas, including both internal and external objects of the six sense-fields. However, due to ignorance (avidyā), the mental faculty’s capacity to perceive dharmas is restricted, forcing reliance on the six consciousnesses arising from the five sense faculties to perceive outwardly. If ignorance is eliminated, restoring the mental faculty’s full function, then it becomes unnecessary to use the six consciousnesses arising from the five sense faculties to perceive dharmas outwardly. The mental faculty alone can perceive dharmas, allowing the five sense faculties to rest and the six consciousnesses to cease.

Through cultivating the "Delight in Seeing Illumination Vajra Samādhi" taught by the World-Honored One, Aniruddha trained to perceive dharmas with the mental faculty—seeing inward without using the eye faculty. As a result, he could perceive the ten-direction worlds with utter clarity, profound truth, and vivid reality—as clearly as looking at a fruit in his own hand. "Revolving the seeing to trace back to the source" is indeed the perfect penetration method of the mental faculty. Who says the mental faculty cannot perceive the objects of the five sense fields? The mental faculty of the great Arhat Aniruddha could perceive the ten-direction worlds—clearly, profoundly, and truly—seeing all forms, sounds, scents, tastes, touches, and dharmas without exception. Through realization via the mental faculty, he attained samādhi, rendering the mental consciousness (mano-vijñāna) unnecessary. Thus, the notion of attaining fruition through the mental consciousness is the greatest absurdity.